Surgical laser systems and laser lithotripsy techniques

ABSTRACT

A laser fiber for use in performing a medical laser treatment includes an optical fiber and a fiber tip. The optical fiber includes a terminating end surface at a distal end. The fiber tip is positioned at the distal end of the optical fiber and includes a transmissive portion and a spacer portion. Laser energy discharged from the terminating end surface of the optical fiber is transmitted through the transmissive portion. The spacer portion defines a distal terminating end of the fiber tip that is spaced a predetermined distance from the terminating end surface of the optical fiber. The predetermined distance is set for shock wave generation for calculus destruction at the distal terminating end of the fiber tip.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on and claims the benefit of U.S.provisional patent application Ser. No. 62/054,582, filed Sep. 24, 2014,and the present application is a continuation of InternationalApplication No. PCT/US2015/051687, filed on Sep. 23, 2015. The contentsof each of the above-identified applications are hereby incorporated byreference in their entirety.

BACKGROUND

Embodiments of the present invention generally relate to laser fibersfor performing a medical laser treatment.

Medical lasers have been used in various practice areas, such as, forexample, urology, neurology, otorhinolaryngology, general anestheticophthalmology, dentistry, gastroenterology, cardiology, gynecology, andthoracic and orthopedic procedures. Generally, these procedures requireprecisely controlled delivery of laser energy as part of the treatmentprotocol.

The treatment of kidney or bladder calculi or stones, Lithotripsy, iscurrently achieved through either ESWL (extracorporeal shock wavelithotripsy), surgery, or use of a laser (laser lithotripsy). In thelaser application, a holmium doped yttrium aluminium garnet (Ho:YAG)laser rod, or a thulium doped yttrium aluminium garnet (Tm:YAG) laserrod, are used to produce laser energy having a wavelength of around2000-2100 nm to break up stones of all types. The laser energy istypically in the form of a train of laser pulses, each having long pulsewidths, such as approximately a few hundred microseconds. It is believedthat a thermo-mechanical mechanism of action is in play for breaking upthe stones, namely the laser energy superheats fluid in the vicinity ofthe stone, and creates a vaporization bubble. The vaporization bubblethen expands as a shockwave and destabilizes the stone, causing it tofragment.

There is a continuous demand for improvements to laser lithotripsy andother laser procedures, such as improved laser fibers for deliveringlaser energy to the targeted stone or tissue.

SUMMARY

Embodiments of the present invention generally relate to a laser fiberfor use in performing a medical laser treatment, such as laserlithotripsy, surgical laser systems utilizing such laser fibers, andmethods of performing laser lithotripsy procedures using the laserfibers. In some embodiments, the laser fiber includes an optical fiberand a fiber tip. The optical fiber includes a terminating end surface ata distal end. The fiber tip is positioned at the distal end of theoptical fiber and includes a transmissive portion and a spacer portion.Laser energy discharged from the terminating end surface of the opticalfiber is transmitted through the transmissive portion. The spacerportion defines a distal terminating end of the fiber tip that is spaceda predetermined distance from the terminating end surface of the opticalfiber. The predetermined distance is set for shock wave generation forcalculus destruction at the distal terminating end of the fiber tip.

Embodiments of the surgical laser system include a laser generator andthe optical fiber formed in accordance with one or more embodiments. Thelaser generator is configured to output laser energy that is opticallycoupled to a proximal end of the optical fiber. The laser energy istransmitted through the optical fiber and is discharged through theterminating end surface of the optical fiber and the fiber tip.

In some embodiments of a method of fragmenting a calculus, the calculusis engaged with the terminating end of the fiber tip to position theterminating end surface of the optical fiber at the predetermineddistance from the calculus. Laser energy is transmitted through theoptical fiber. The laser energy is discharged through the terminatingend surface of the optical fiber and the calculus is exposed to thelaser energy while the calculus is maintained at the predetermineddistance from the terminating end surface using the spacer portion. Thecalculus is fragmented in response to the exposure to the laser energy.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter. The claimed subject matter is not limited to implementationsthat solve any or all disadvantages noted in the Background.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary surgical laser system inaccordance with embodiments of the invention.

FIGS. 2 and 3 are simplified side cross-sectional views of a distal endof exemplary laser fibers in accordance with embodiments of theinvention.

FIG. 4 is a simplified cross-sectional view of a fiber tip of FIG. 3taken generally along line 4-4.

FIGS. 5-7 are simplified side cross-sectional views of a distal end ofexemplary laser fibers in accordance with embodiments of the invention.

FIG. 8 shows photos of laser lithotripsy operations using exemplarylasers.

FIG. 9 is a chart illustrating a relationship between an ablation volumeand a spacing between a terminating end surface or fiber tip of anoptical fiber and a calculus for two exemplary lasers.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the present invention generally relate to laser fibersfor use in performing a medical laser treatment, such as laserlithotripsy, surgical laser systems utilizing such laser fibers, andmethods of performing laser lithotripsy procedures using the laserfibers. Embodiments of the invention are described more fullyhereinafter with reference to the accompanying drawings. The variousembodiments of the invention may, however, be embodied in many differentforms and should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the invention to those skilled in the art. Elements that areidentified using the same or similar reference characters refer to thesame or similar elements.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, if an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. Thus, a first element could be termed a secondelement without departing from the teachings of the present invention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 is a schematic diagram of an exemplary surgical laser system 100,which includes a laser fiber 102 in accordance with one or moreembodiments of the invention. FIGS. 2-7 are simplified cross-sectionalviews of exemplary laser fibers 102 in accordance with embodiments ofthe invention. FIG. 4 is a simplified cross-sectional view of a fibertip of FIG. 4 taken generally along line 4-4.

In some embodiments, the system 100 comprises a laser generator 104 thatgenerates laser energy 106 and a waveguide 108 optically coupling thelaser generator 104 to the laser fiber 102. The laser fiber 102 eitherincludes the waveguide 108 or is optically coupled to the waveguide 108.The laser energy 106 is discharged from a distal end of the laser fiber102, i.e., the end of the laser fiber 102 that is adjacent to thetreatment site of a patient, and can be used to perform a desiredmedical laser procedure, such as tissue ablation, or urinary or kidneystone fragmentation. In some embodiments, the system 100 includes aprobe 110 (FIG. 1), in which at least a distal end of the laser fiber102 is supported.

In some embodiments, the laser generator 104 comprises one or moreconventional laser sources, such as laser resonators, that produce thelaser energy 106 having desired properties. In some embodiments, thesystem 100 produces the laser energy 106 in the form of a pulse train orcontinuous wave. In some embodiments, the laser generator 102 includesQ-switched laser rods to produce the laser energy 106, such as, forexample, a holmium doped yttrium aluminium garnet (Ho:YAG) laser rod, athulium doped yttrium aluminium garnet (Tm:YAG) laser rod, or otherconventional laser rod suitable for producing the desired laser energy106. In some embodiments the laser energy 106 has a power ofapproximately 1-50 W, a pulse repetition frequency of 1-2000 Hz. and anenergy level of 1 mJ-5 J. Laser energy 106 having other parameters mayalso be used.

In some embodiments, the laser fiber 102 includes an optical fiber 112and a fiber tip 114. The optical fiber 112 includes a terminating endsurface 116 at a distal end 118. In some embodiments, the fiber tip 114includes a distal terminating end 120 that is spaced a predetermineddistance 122 from the terminating end surface 116 of the optical fiber112. In some embodiments, the fiber tip 114 operates to protect thedistal end 118 of the optical fiber. For instance, the fiber tip 114 canprevent or reduce damage to the distal end 118 of the optical fiber 112that can occur during medical laser treatments due to contact betweenthe distal end 118 of the optical fiber 112 and the targeted object forthe laser energy 106, such as a calculus (i.e., kidney or bladder stone)124 or tissue. In some embodiments, the fiber tip 114 forms a sealedcavity 125 around the terminating end surface 116 of the optical fiber,as shown in FIG. 2.

In some embodiments, the predetermined distance or spacing 122 isgenerally set to alleviate/control damage to the distal end 118 of theoptical fiber 112, manipulate (focus or diffuse) a shock wave generatedduring laser lithotripsy, and improve ablation efficiency. FIG. 8 showsphotos of laser lithotripsy operations using a Ho:YAG laser, and aTm:YAG laser that show a bubble formation process and oscillationsduring the laser-stone interaction. FIG. 9 is a chart illustrating arelationship between an ablation volume and the spacing 122 between theterminating end surface 116 or fiber tip of the optical fiber 112 andthe calculus 124 for a Ho:YAG laser (1.0 J, 10 Hz, ˜109 μs) and a Tm:YAGlaser (40 mJ, 250 Hz, 190 ns). The chart illustrates that the ablationefficiency for the Ho:YAG laser is higher when the spacing 122 is 0.5 mmas compared to when the surface 116 of the optical fiber 112 is incontact with the calculus 124. Additionally, the chart shows that theablation efficiency of the Tm:YAG laser is similar over the spacing 122of 0-0.5 mm. Thus, the spacing 122 between the surface 116 of theoptical fiber 112 and the targeted object (e.g., calculus 124) providedby the fiber tip 114 can allow for efficient ablation of the targetedobject while protecting the optical fiber 122. In some embodiments, thedistance 122 is approximately 0.1-4 mm. In some embodiments, thedistance 122 is 0.1 mm-1 mm.

In some embodiments, the fiber tip 114 is attached to the laser fiber112, as shown in FIGS. 2 and 5-7. In some embodiments, this involvesattaching the fiber tip 114 to a core of the optical fiber 112, claddingof the optical fiber 112, and/or a jacket surrounding the cladding andcore of the optical fiber 112, which are not shown in order to simplifythe illustrations. In some embodiments, the fiber tip 114 is removablyattached to the optical fiber 112. In some embodiments, the fiber tip114 may be attached to the distal end 118 of the optical fiber 112 byhand, and may also be detached from the optical fiber 112 by hand.

In some embodiments, the optical fiber 112 may be supported within afiber support 126, as shown in FIG. 3. The fiber support 126 may be atubular member through which the optical fiber 112 is inserted. In someembodiments, the fiber tip 114 attaches directly to the fiber support126 rather than the optical fiber 112, as shown in FIG. 3. In someembodiments, the fiber tip 114 is removably attachable to the fibersupport 126. In some embodiments, the attachment and removal of thefiber tip 114 from the fiber support 126 may be performed by hand.

In some embodiments, the fiber tip 114 includes a sleeve portion 128that facilitates attachment of the fiber tip 114 to either the opticalfiber 112 (FIG. 2) or a fiber support 126 (FIG. 3). In some embodiments,at least a proximal end 130 of the sleeve portion 128 forms a socketthat is configured to receive the distal end 118 of the optical fiber112 (FIG. 2) or a distal end 132 of the fiber support 126 (FIG. 3). Insome embodiments, the sleeve portion 128 includes a shoulder 134 that isconfigured to engage the terminating end surface 116 of the opticalfiber 112 (FIG. 2) or an end surface 136 of the fiber support 126 (FIG.3) to position the terminating end 120 of the fiber tip 114 at thedesired distance 122 from the terminating end surface 116 of the opticalfiber 112.

In some embodiments, the fiber tip 114 includes a transmissive portion140, through which the laser energy 106 discharged from the terminatingend surface 116 of the optical fiber 112 is transmitted. In someembodiments, the laser energy 106 is discharged through the transmissiveportion 140 along a longitudinal axis of the optical fiber 112.

In some embodiments, the fiber tip 114 includes a spacer portion 142that defines the distal terminating end 120 of the fiber tip 114. Insome embodiments, the transmissive portion 140 includes the spacerportion 142, as shown in FIGS. 2, 3, 6 and 7. In some embodiments, thespacer portion 142 extends distally from the transmissive portion 140,as shown in FIG. 5. In some embodiments, the distal terminating end 120of the spacer portion 142 is annular, as shown in FIG. 5. In otherembodiments, the distally extending spacer portion 142 may comprise oneor more projections.

In some embodiments, the sleeve portion 128 supports the transmissiveportion 140 and the spacer portion 142. In some embodiments, the sleeveportion 128 surrounds the distal end 118 of the optical fiber 112. Insome embodiments, the sleeve portion 128, the transmissive portion 140,and the spacer portion 142 are formed as a single component, as shown inFIG. 7.

In some embodiments, components of the fiber tip 114, such as thetransmissive portion 140, the spacer portion 142, and/or the sleeveportion 128, are formed of sapphire or hard glass.

In some embodiments, the transmissive portion 140 includes one or morelenses that assist in focusing or diffusing the laser energy 106 that isdirected to the targeted object, such as a calculus 124. In someembodiments, a lens 144 is located at the distal end of the transmissiveportion 140, as shown in phantom in FIG. 2. In some embodiments, thetransmissive portion 140 includes a lens 146 located at a proximal endof the transmissive portion 140, as shown in phantom in FIG. 2.

In some embodiments, the distal terminating end 120 of the fiber tip 114includes a convex surface 150, as shown in FIGS. 6 and 7. The surface150 may operate as the distal lens 144 (FIG. 2). In some embodiments,the convex surface 150 operates to diffuse the shock wave that occursduring laser lithotripsy to reduce retropulsion of the calculus or stone124.

Another embodiment of the invention is directed to a method offragmenting a calculus using a laser fiber 102 formed in accordance withone or more embodiments of the present invention. In the method, thecalculus 124 is engaged with the terminating end 120 of the fiber tip114 to position the terminating end surface 116 of the optical fiber 112at the predetermined distance 122 from the calculus, as shown in FIGS.2, 3 and 5. Laser energy 106 is then transmitted through the opticalfiber 112 and discharged through the terminating end surface 116. Thecalculus or stone 124 is exposed to the laser energy 106 while thecalculus is at the predetermined distance 122 from the terminating endsurface 116. The calculus is then fragmented responsive to the exposureof the calculus to the laser energy 106 and the shock wave generatedthereby.

Additionally, because fiber tips 114 according to the embodiments of thepresent invention can be detachably mounted to the laser fiber 102, thefiber tips 114 can be designed for specific procedures, types ofcalculi, etc. Accordingly, a single laser fiber can be used withdifferent fiber tips 114 to perform multiple different types ofprocedures more efficiently and with better outcomes.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1.-20. (canceled)
 21. A laser device comprising: an optical fiberincluding a proximal end configured to receive a laser energy, and adistal end with a distal terminating end surface configured to transmitthe laser energy; and a fiber tip at the distal end of the opticalfiber, the fiber tip including: a proximal end attached to the distalend of the optical fiber; a distal end with a distal terminating endsurface; and a transmissive body at or adjacent the distal end of thefiber tip, the transmissive body being spaced apart from the distalterminating end surface of the optical fiber and comprising: a solidinterior configured to receive the laser energy from the distalterminating end surface of the optical fiber and transmit the laserenergy toward the distal terminating end surface of the fiber tip. 22.The laser device according to claim 21, wherein the distal terminatingend surface of the fiber tip is spaced a distance from the distalterminating end surface of the optical fiber.
 23. The laser deviceaccording to claim 22, wherein the distance is between 0.10 mm and 4 mm.24. The laser device according to claim 21, wherein the fiber tip isremovably attached to the distal end of the optical fiber.
 25. The laserdevice according to claim 21, wherein the optical fiber is containedwithin a fiber support, and the fiber tip is attached to the fibersupport.
 26. The laser device according to claim 21, wherein the fibertip includes an annular spacer extending distally from the transmissivebody, and the annular spacer is a distalmost portion of the device. 27.The laser device according to claim 26, wherein each of the solidtransmissive cylinder and the annular spacer includes a sapphire. 28.The laser device according to claim 21, wherein the fiber tip furthercomprises a sleeve surrounding at least a portion of the transmissivebody and connects the transmissive body to the distal end of the opticalfiber.
 29. The laser device according to claim 28, wherein the sleeveincludes a proximal facing shoulder engaging a distalmost portion of theoptical fiber, and the laser device further comprises: a first lensattached to a proximal end of the transmissive body and disposedentirely within the sleeve; and a second lens attached to a distal endof the transmissive body and disposed entirely outside the sleeve,wherein a sealed cavity is disposed entirely between the first lens andthe distalmost portion of the optical fiber, and at least a portion ofthe transmissive body is provided outside the sleeve.
 30. The laserdevice according to claim 21, further including a lens configured tofocus the laser energy transmitted from the distal terminating endsurface of the optical fiber.
 31. The laser device according to claim21, wherein the lens portion is positioned at a proximal end of thetransmissive body.
 32. The laser device according to claim 21, whereinthe proximal end of the laser fiber is configured to be opticallyconnected to a laser generator and receive the laser energy from thelaser generator.
 33. The laser device according to claim 21, furtherincluding: a sealed interior cavity between the distal terminating endsurface of the optical fiber and a proximal end of the transmissivebody, wherein the fiber tip further includes at least one shoulderconfigured to maintain a distance between the transmissive body and theoptical fiber.
 34. The laser device according to claim 21, wherein adistal end of the transmissive body is convex when viewed from aposition distal to the transmissive body.
 35. A laser device comprising:a laser fiber comprising: an optical fiber extending along alongitudinal axis between a proximal end and a distal end, the distalend of the optical fiber including a distal terminating end surface; afiber tip at the distal end of the optical fiber, the fiber tipincluding: a proximal end attached to the distal end of the opticalfiber, a distal end including a distal terminating end surface spaced apredetermined distance from the distal terminating end surface of theoptical fiber along the longitudinal axis, and a solid transmissivecylinder at or adjacent the distal end, the cylinder including: a firstend configured to receive a laser energy from the distal terminating endsurface of the optical fiber, a second end configured to transmit thelaser energy from the laser device, and at least one lens attached tothe second end or the first end.
 36. The laser device according to claim35, wherein the fiber tip includes an annular spacer extending from thesecond end of the solid transmissive cylinder, the annular spacerincluding the distal terminating end surface and being a distalmostportion of the fiber tip.
 37. The laser device according to claim 36,wherein: the laser device includes a laser generator including one of aTm:YAG laser or a Ho:YAG laser; the predetermined distance is between0.10 mm and 4 mm; and each of the fiber tip, the solid transmissivecylinder, and the annular spacer is made of a sapphire.
 38. A laserdevice comprising: an optical fiber extending along a longitudinal axisbetween a proximal end configured to receive a laser energy, and adistal end configured to transmit the laser energy; a fiber tip at thedistal end of the optical fiber, including: a lumen extending along thelongitudinal axis, a proximal end attached to the distal end of theoptical fiber, a distal end, and a transmissive body supported in thelumen of the fiber tip, the body including a first end, a lens attachedto the first end and configured to receive the laser energy from thedistal end of the optical fiber, and a second end configured to transmitthe laser energy out of the laser device, wherein: the distal end of thefiber tip is spaced a first distance from the distal end of the opticalfiber along the longitudinal axis.
 39. The laser device according toclaim 38, further including: an annular spacer extending from the secondend of the transmissive body, the annular spacer being a distalmostportion of the fiber tip.
 40. The laser device according to claim 38,wherein the second end of the transmissive body includes a lens.